Size dependence of structure and magnetic properties of La0.7Sr0.3MnO3 nanoparticles

Using a sol-gel method, Perovskite-type manganese oxides La0.7Sr0.3MnO3 nanoparticles with various grain sizes were prepared. A transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were employed to identify the microstructure. A Rietveld refinement method was applied to determine crystallographic parameters. Results show that prepared-nanoparticles are single crystal, the edge length of the unit cell becomes longer and the angle between the edges becomes less deviated from 60degrees as the grain sizes decrease, and the crystal symmetry changes from rhombohedral to cubic as D similar to 16 nm. The magnetic properties were investigated using a vibrating sample magnetometer, the magnetization is significantly lower than that of bulk sample. (C) 2004 Elsevier B.V. All rights reserved.